Boeing B-17B Fortress

Last revised July 16, 1999

The B-17B (Model 299M) was the first production version of the B-17
series. Originally, it was designated Model 299E by Boeing, but
changes in Air Corps specifications were considered sufficient to
justify a new factory designation.

Outwardly, the B-17B differed from the Y1B-17 only in having a revised
rudder with larger area, larger wing flaps, and a revised nose that
eliminated the greenhouse gun turret in the upper nose and the belly
bomb-aiming window in the lower nose. The upper nose turret was
replaced by a simple socket for a 30-inch flexible machine gun in the
extreme tip of the nose. The bomb-aiming window was replaced by an
optical flat in the lower part of the Plexiglas nose fairing. The
revised nose resulted in a decrease in overall length of 7 inches. A
small plastic dome was added to the cabin roof. More-powerful
R-1820-51 engines were fitted which delivered a maximum power of 1200
hp for takeoff and 900 hp at 25,000 feet. Internally, many systems
were changed and crew members were relocated. The brakes were changed
from pneumatic to hydraulic.

The famous Norden bombsight was mounted above the bomb-aiming window.
The Norden bombsight was a gyro-stabilized bomb sight originally
developed by Carl L. Norden and Capt. Frederick I. Entwistle. It
was capable of quickly calculating the plane's forward velocity and
drift and making corrections in order to achieve a hit. In later
versions, the Norden bombsight was connected with the autopilot, and
actually flew the plane during the final run in to the target. In the
press releases of the day, the bombsight was claimed to be so accurate
that it could "put bombs in a pickle barrel". The Norden bombsight
was considered so secret that it was installed, carefully covered, in
the aircraft only immediately before takeoff and was taken out
immediately after landing, always under the supervision of an armed
guard.

The first B-17B (38-211) flew for the first time at Seattle on June
27, 1939. 39 B-17Bs were built in a single run at Boeing. However,
the USAAC serial numbers were scattered over several batches,
indicating how difficult it was at the time for the Air Corps to
obtain funding--it could only order B-17Bs a few at a time.

All 39 of the B-17Bs were delivered to the USAAC between July 29, 1939
and March 30, 1940. The B-17Bs were issued to the 2nd, 7th, and 19th
Bombardment Groups, except for the first example which was retained at
Wright Field for tests.

In November of 1939, seven Fortresses flew from Langley Field to Rio
de Janeiro, Brazil on a good-will mission. All planes returned safely
with no major incidents, once again demonstrating the safety and
reliability of the B-17 design.

Many B-17Bs were modernized in 1940-41 to use such such features as
the flush-type side openings for 0.50-inch machine guns that had been
introduced on the B-17C.

A B-17B serving with the 41st Reconnaissance Squadron of the 2nd Bomb
Group based in Newfoundland attacked a U-boat on October 27, 1941.
Although the U-boat was undamaged in the attack, this incident was the
first in which bombs were dropped in anger by the Army Air Forces in
action against German forces. Since the United States was officially
not at war with Germany at the time, the incident was not reported in
the press.